Aim To investigate the effects of cerivastatin on expression of matrix metalloproteinase (MMP-9) and CD40 in THP-1 cells. Methods THP-1 cells were incubated with increasing concentration of cerivastatin. MMP-9 and CD40 mRNA were detected by RT-PCR, MMP-9 concentration in media were assayed by ELISA. Results Cerivastatin inhibited the expression of CD40 and MMP-9 concentration dependently. At 0.01 μmol/L, the mRNA levels of CD40 and MMP-9 were not significantly decreased. But expression of CD40 and MMP-9 mRNA were significant down-regulated at 1 to 10 μmol/L; Level of MMP-9 concentration in media decreased from 0.469±0.06 to 0.243±0.04 and 0.039±0.01 respectively at 1 or 10 μmol/L(p<0.05). Conclusions Cerivastatin inhibited the expression of CD40 and MMP-9 in THP-1 cells, decrease the MMP-9 concentration in media, it suggest that HMG-CoA reductase inhibitors may suppress inflammatory signaling and plaque disruption which responsible for clinical acute coronary syndrome.